Subject: Re: [PATCH 06/11] mux: Add Pericom PI3USB30532 Type-C mux driver
From: Peter Rosin <peda@axentia.se>
To: Hans de Goede <hdegoede@redhat.com>,
        MyungJoo Ham <myungjoo.ham@samsung.com>,
        Chanwoo Choi <cw00.choi@samsung.com>,
        Guenter Roeck <linux@roeck-us.net>,
        Heikki Krogerus <heikki.krogerus@linux.intel.com>,
        Darren Hart <dvhart@infradead.org>,
        Andy Shevchenko <andy@infradead.org>,
        Mathias Nyman <mathias.nyman@intel.com>
Cc: platform-driver-x86@vger.kernel.org, devel@driverdev.osuosl.org,
        Kuppuswamy Sathyanarayanan 
        <sathyanarayanan.kuppuswamy@linux.intel.com>,
        Sathyanarayanan Kuppuswamy Natarajan <sathyaosid@gmail.com>,
        linux-kernel@vger.kernel.org,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-usb@vger.kernel.org
References: <20170901214845.7153-1-hdegoede@redhat.com>
 <20170901214845.7153-7-hdegoede@redhat.com>
 <600628b1-5555-1b96-743f-0593af5a6069@axentia.se>
Organization: Axentia Technologies AB
Message-ID: <ee9bd3e3-fe77-bece-da7c-c1a62265a510@axentia.se>
Date: Tue, 5 Sep 2017 09:46:58 +0200
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On 2017-09-04 13:19, Peter Rosin wrote:
> Hi!
> 
> One comment inline...

Oh, and one more small nit, I think you should do

s/pi3usb30532_mux/pi3usb30532/g

to shorten the identifiers a bit. The _mux suffix (or infix) is kind of
selfevident from where the file lives anyway. pi3usb30532_mux_set_mux in
particular feels a bit much....

Cheers,
peda

> On 2017-09-01 23:48, Hans de Goede wrote:
>> Add a driver for the Pericom PI3USB30532 Type-C cross switch /
>> mux chip found on some devices with a Type-C port.
>>
>> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
>> ---
>>  drivers/mux/Kconfig       | 10 +++++
>>  drivers/mux/Makefile      |  2 +
>>  drivers/mux/pi3usb30532.c | 97 +++++++++++++++++++++++++++++++++++++++++++++++
>>  3 files changed, 109 insertions(+)
>>  create mode 100644 drivers/mux/pi3usb30532.c
>>
>> diff --git a/drivers/mux/Kconfig b/drivers/mux/Kconfig
>> index 17938918bf93..19a3065c34e6 100644
>> --- a/drivers/mux/Kconfig
>> +++ b/drivers/mux/Kconfig
>> @@ -58,4 +58,14 @@ config MUX_MMIO
>>  	  To compile the driver as a module, choose M here: the module will
>>  	  be called mux-mmio.
>>  
>> +config MUX_PI3USB30532
>> +	tristate "Pericom PI3USB30532 Type-C cross switch driver"
>> +	depends on I2C
>> +	help
>> +	  This driver adds support for the Pericom PI3USB30532 Type-C cross
>> +	  switch / mux chip found on some devices with a Type-C port.
>> +
>> +	  To compile the driver as a module, choose M here: the module will
>> +	  be called mux-pi3usb30532.
>> +
>>  endmenu
>> diff --git a/drivers/mux/Makefile b/drivers/mux/Makefile
>> index a12e812c7966..7563dbf04593 100644
>> --- a/drivers/mux/Makefile
>> +++ b/drivers/mux/Makefile
>> @@ -7,9 +7,11 @@ mux-adg792a-objs		:= adg792a.o
>>  mux-gpio-objs			:= gpio.o
>>  mux-mmio-objs			:= mmio.o
>>  mux-intel_cht_usb_mux-objs	:= intel_cht_usb_mux.o
>> +mux-pi3usb30532-objs		:= pi3usb30532.o
>>  
>>  obj-$(CONFIG_MULTIPLEXER)	+= mux-core.o
>>  obj-$(CONFIG_MUX_ADG792A)	+= mux-adg792a.o
>>  obj-$(CONFIG_MUX_GPIO)		+= mux-gpio.o
>>  obj-$(CONFIG_MUX_MMIO)		+= mux-mmio.o
>>  obj-$(CONFIG_MUX_CHT_USB_MUX)	+= mux-intel_cht_usb_mux.o
>> +obj-$(CONFIG_MUX_PI3USB30532)	+= mux-pi3usb30532.o
>> diff --git a/drivers/mux/pi3usb30532.c b/drivers/mux/pi3usb30532.c
>> new file mode 100644
>> index 000000000000..fa8abd851520
>> --- /dev/null
>> +++ b/drivers/mux/pi3usb30532.c
>> @@ -0,0 +1,97 @@
>> +/*
>> + * Pericom PI3USB30532 Type-C cross switch / mux driver
>> + *
>> + * Copyright (c) 2017 Hans de Goede <hdegoede@redhat.com>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation, or (at your option)
>> + * any later version.
>> + */
>> +
>> +#include <linux/i2c.h>
>> +#include <linux/kernel.h>
>> +#include <linux/module.h>
>> +#include <linux/mux/consumer.h> /* For the MUX_USB_* defines */
>> +#include <linux/mux/driver.h>
>> +
>> +#define PI3USB30532_CONF			0x00
>> +
>> +#define PI3USB30532_CONF_OPEN			0x00
>> +#define PI3USB30532_CONF_SWAP			0x01
>> +#define PI3USB30532_CONF_4LANE_DP		0x02
>> +#define PI3USB30532_CONF_USB3			0x04
>> +#define PI3USB30532_CONF_USB3_AND_2LANE_DP	0x06
>> +
>> +struct pi3usb30532_mux {
>> +	struct i2c_client *client;
>> +};
>> +
>> +static int pi3usb30532_mux_set_mux(struct mux_control *mux_ctrl, int state)
>> +{
>> +	struct pi3usb30532_mux *mux = mux_chip_priv(mux_ctrl->chip);
> 
> The "mux" variable name is used for the mux_control in other drivers, and
> I don't think the private data is needed. Like so:
> 
> static int pi3usb30532_mux_set_mux(struct mux_control *mux, int state)
> {
> 	struct i2c_client *i2c = to_i2c_client(mux->chip->dev.parent);
> 
> ...
> 
> Cheers,
> Peter
> 
>> +	u8 conf = PI3USB30532_CONF_OPEN;
>> +
>> +	switch (state & ~MUX_USB_POLARITY_INV) {
>> +	case MUX_USB_NONE:
>> +		conf = PI3USB30532_CONF_OPEN;
>> +		break;
>> +	case MUX_USB_DEVICE:
>> +	case MUX_USB_HOST:
>> +		conf = PI3USB30532_CONF_USB3;
>> +		break;
>> +	case MUX_USB_HOST_AND_DP_SRC:
>> +		conf = PI3USB30532_CONF_USB3_AND_2LANE_DP;
>> +		break;
>> +	case MUX_USB_DP_SRC:
>> +		conf = PI3USB30532_CONF_4LANE_DP;
>> +		break;
>> +	}
>> +
>> +	if (state & MUX_USB_POLARITY_INV)
>> +		conf |= PI3USB30532_CONF_SWAP;
>> +
>> +	return i2c_smbus_write_byte_data(mux->client, PI3USB30532_CONF, conf);
>> +}
>> +
>> +static const struct mux_control_ops pi3usb30532_mux_ops = {
>> +	.set = pi3usb30532_mux_set_mux,
>> +};
>> +
>> +static int pi3usb30532_mux_probe(struct i2c_client *client)
>> +{
>> +	struct device *dev = &client->dev;
>> +	struct pi3usb30532_mux *mux;
>> +	struct mux_chip *mux_chip;
>> +
>> +	mux_chip = devm_mux_chip_alloc(dev, 1, sizeof(*mux));
>> +	if (IS_ERR(mux_chip))
>> +		return PTR_ERR(mux_chip);
>> +
>> +	mux_chip->ops = &pi3usb30532_mux_ops;
>> +	mux_chip->mux[0].states = MUX_USB_STATES;
>> +	mux = mux_chip_priv(mux_chip);
>> +	mux->client = client;
>> +
>> +	return devm_mux_chip_register(dev, mux_chip);
>> +}
>> +
>> +static const struct i2c_device_id pi3usb30532_mux_table[] = {
>> +	{ "pi3usb30532" },
>> +	{ }
>> +};
>> +MODULE_DEVICE_TABLE(i2c, pi3usb30532_mux_table);
>> +
>> +static struct i2c_driver pi3usb30532_mux_driver = {
>> +	.driver = {
>> +		.name = "pi3usb30532",
>> +	},
>> +	.probe_new = pi3usb30532_mux_probe,
>> +	.id_table = pi3usb30532_mux_table,
>> +};
>> +
>> +module_i2c_driver(pi3usb30532_mux_driver);
>> +
>> +MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
>> +MODULE_DESCRIPTION("Pericom PI3USB30532 Type-C mux driver");
>> +MODULE_LICENSE("GPL");
>>
>